/*
 * Copyright 2002-2010 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using System.Globalization;
using Spring.Util;

namespace Spring.Globalization.Formatters;

/// <summary>
/// Implementation of <see cref="IFormatter"/> that can be used to
/// format and parse <see cref="DateTime"/> values.
/// </summary>
/// <remarks>
/// <para>
/// <c>DateTimeFormatter</c> uses properties of the
/// <see cref="DateTimeFormatInfo"/> to format and parse <see cref="DateTime"/> values.
/// </para>
/// <para>
/// If you use one of the constructors that accept culture as a parameter
/// to create an instance of <c>DateTimeFormatter</c>, default <c>DateTimeFormatInfo</c>
/// for the specified culture will be used.
/// </para>
/// <para>
/// You can also use properties exposed by the <c>DateTimeFormatter</c> in order
/// to override some of the default formatting parameters.
/// </para>
/// </remarks>
/// <author>Aleksandar Seovic</author>
public class DateTimeFormatter : IFormatter
{
    private DateTimeFormatInfo formatInfo;
    private string format;

    /// <summary>
    /// Initializes a new instance of the <see cref="DateTimeFormatter"/> class
    /// using default <see cref="DateTimeFormatInfo"/> for the current thread's culture.
    /// </summary>
    /// <param name="format">Date/time format string.</param>
    public DateTimeFormatter(string format) : this(format, CultureInfo.CurrentCulture)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="DateTimeFormatter"/> class
    /// using default <see cref="DateTimeFormatInfo"/> for the specified culture.
    /// </summary>
    /// <param name="format">Date/time format string.</param>
    /// <param name="cultureName">The culture name.</param>
    public DateTimeFormatter(string format, string cultureName) : this(format, CultureInfo.CreateSpecificCulture(cultureName))
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="DateTimeFormatter"/> class
    /// using default <see cref="DateTimeFormatInfo"/> for the specified culture.
    /// </summary>
    /// <param name="format">Date/time format string.</param>
    /// <param name="culture">The culture.</param>
    public DateTimeFormatter(string format, CultureInfo culture)
    {
        this.format = format;
        this.formatInfo = culture.DateTimeFormat;
    }

    /// <summary>
    /// Formats the specified <see cref="DateTime"/> value.
    /// </summary>
    /// <param name="value">The value to format.</param>
    /// <returns>Formatted <see cref="DateTime"/> value.</returns>
    /// <exception cref="ArgumentNullException">If <paramref name="value"/> is <c>null</c>.</exception>
    /// <exception cref="ArgumentException">If <paramref name="value"/> is not an instance of <see cref="DateTime"/>.</exception>
    public string Format(object value)
    {
        AssertUtils.ArgumentNotNull(value, "value");
        if (!(value is DateTime))
        {
            throw new ArgumentException("DateTimeFormatter can only be used to format instances of [System.DateTime].");
        }

        return ((DateTime) value).ToString(format, formatInfo);
    }

    /// <summary>
    /// Parses the specified value.
    /// </summary>
    /// <param name="value">The string to parse.</param>
    /// <returns>Parsed <see cref="DateTime"/> value.</returns>
    public object Parse(string value)
    {
        if (!StringUtils.HasText(value))
        {
            return DateTime.MinValue;
        }

        return DateTime.ParseExact(value, format, formatInfo, DateTimeStyles.AllowWhiteSpaces);
    }
}
